Problem: Takahashi loves sorting.

He has a permutation (p_1,p_2,...,p_N) of the integers from 1 through N. Now, he will repeat the following operation until the permutation becomes (1,2,...,N):

* First, we will define high and low elements in the permutation, as follows. The i-th element in the permutation is high if the maximum element between the 1-st and i-th elements, inclusive, is the i-th element itself, and otherwise the i-th element is low.
* Then, let a_1,a_2,...,a_k be the values of the high elements, and b_1,b_2,...,b_{N-k} be the values of the low elements in the current permutation, in the order they appear in it.
* Lastly, rearrange the permutation into (b_1,b_2,...,b_{N-k},a_1,a_2,...,a_k).



How many operations are necessary until the permutation is sorted?

Constraints

* 1 ≤ N ≤ 2×10^5
* (p_1,p_2,...,p_N) is a permutation of the integers from 1 through N.

Input

Input is given from Standard Input in the following format:


N
p_1 p_2 ... p_N


Output

Print the number of operations that are necessary until the permutation is sorted.

Examples

Input

5
3 5 1 2 4


Output

3


Input

5
5 4 3 2 1


Output

4


Input

10
2 10 5 7 3 6 4 9 8 1


Output

6

Solution (in CPP):

Solution:
//Love and Freedom.
#include<algorithm>
#include<cstring>
#include<cmath>
#include<cstdio>
#define inf 20021225
#define ll long long
#define N 200010
using namespace std;
int read()
{
	int f=1,s=0; char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-') f=-1; ch=getchar();}
	while(ch>='0'&&ch<='9')	s=s*10+ch-'0',ch=getchar();
	return f*s;
}
int a[N],n,t[N],f[N];
bool check(int x,int y,int z){return (x<y&&y<z)||(y<z&&z<x)||(z<x&&x<y);}
int main()
{
	n=read();
	for(int i=1;i<=n;i++)	a[read()]=i;
	for(int i=n-1;i;i--)
	{
		if(!t[i+1])
		{
			if(a[i]>a[i+1])	t[i]=1,f[i]=a[i+1];
		}
		else
		{
			if(check(f[i+1],a[i],a[i+1]))
				t[i]=t[i+1],f[i]=f[i+1];
			else
				t[i]=t[i+1]+1,f[i]=a[i+1];
		}
	}
	printf("%d\n",t[1]);
	return 0;
}